Investigations of complexes of copper(II) chloride with phenylpyrazoles

The crystal structures of dichlorobis(3,5-diphenylpyrazole-N-2)copper(TI), [CuCl2(C15H12N2)(2)], (I), dichlorobis(5-phenylpyrazole-N-2)copper(II),[CuC l2(C9H8N2)(2)], (II), and dichlorobis(1-phenylpyrazole-N-2)copper(II [CuCl2 (C9H8N2)(2)], (III), have been determined from X-ray diffraction data. Ther e are significant differences in the coordination of the Cl- ions to the Cu 2+ ion. The coordination of the Cu2+ ion is distorted square pyramidal in c ompounds (I) and (II), and distorted tetrahedral in (III). All available N- H groups form hydrogen bonds, which are intra- and intermolecular in (I), a nd intramolecular in (II). An N-H group in (I) forms a bifurcated hydrogen bond. Intermolecular intereactions between neighbouring molecules form dime rs and chains in (I) and (II), respectively.